The Research Services Core provides basic support for all five of the projects in this Program. The Core facilities in the Department of Physiology at MCW evolved from the original Program Project group. As the Department has grown investigators have found these facilities to be increasingly essential to their research. The current core facilities are supported in part by the Department and non-PPG research grants, yet the single largest user and supporter of the Research Services Core remains this program. The continued financial support of these core facilities by the PPG is essential for the work proposed in this Program, without these cores, the research proposed in this application could not be conducted. The Research Services Core of this program has expanded in both scope and size during the previous grant period with the addition of new activities in Histology, Microscopy, and Image Processing. Eleven individuals currently staff the Research Services Core, each with significant experience in a broad range of activities that support the research infrastructure within the Department of Physiology. This staff is divided among one or more support groups, computer, analytical, animal modeling, microscopy, machine and electronics, and instrument service. Based on the amount of crossover in the activities of these groups we have now found it more productive to unify their efforts into one core under the supervision of Dr. Andrew S. Greene. Based on these natural divisions, the Research Services Core serves 7 main functions within the program project; computer support, analytical and statistical consultation, chronic animal monitoring, microscopy and image processing, custom machine and electronic fabrication, instrument service, and rat colony maintenance.